• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.22-26
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• 2007

In the fibre to the home (FTTH) era, it is expected that broadband network provisioning will require thousands of optical fibres to be accommodated in a central office for optical access networks. An optical fibre line testing system could be used to reduce maintenance costs and improve service availability depending on the PON's element manager capabilities and the maintenance procedures adopted by the network supplier. When monitoring optical fibres transmitting communication lights, a wavelength of 1625 nm is used for maintenance testing. The splitter installed optical filters allow the communication light to pass but that cut off the test light in the front of optical line terminals (OLTs) and optical network terminals (ONTs). In the economic point of view, We design new planer lightwave circuit splitter embedded filtter and study it optical property.

• International Journal of Precision Engineering and Manufacturing
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• v.1 no.1
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• pp.56-61
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• 2000

We present a fast inspection method of machine vision for in-line quality assurance of liquid crystal displays(LCD) and plasma display panels(PDP). The method incorporates an optical spatial filter in the Fourier plane of the imaging optics to block the normal periodic pattern, extracting only defects real time without relying on intensive software image process. Special emphasis is on designing a collimated white light source to provide high degree of spatial coherence for effective real time Fourier transform. At the same time, a low level of temporal coherence is attained to improve defect detection capabilities by avoiding undesirable coherent noises. Experimental results show that the proposed inspection method offers a detection accuracy of 15% tolerance, which is sufficient for industrial applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.324-325
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• 2006

In order to develop high efficiency white organic light-emitting diodes (OLEDs), OLED devices consisted of red and blue emitting layers (EMLs) were fabricated and the effect of respective layer thickness and the order of layer stacking on the luminous efficiency was evaluated Red/blue structure showed higher efficiency than blue/red, due to the higher exiton formation. In the blue layer of red/blue structure. However, the efficiency of the red/blue significantly depended on the thickness of the red layer, whereas the thickness of the blue layer was not affect so much. The optimum thickness of the red layer was 20 ${\AA}$, where the luminous and power efficiencies were 155 cd/A and 10.51 lm/W at 1000~3000$cd/m^2$ respectively and the maximum luminance was about 80,000 $cd/m^2$.

• Korean Journal of Optics and Photonics
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• v.13 no.2
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• pp.89-91
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• 2002

A test method that can measure the parallelism and the surface figure of an nontransparent plate using visible light is proposed. The testing system consists of a Twyman-Green interferometer. In addition, test results for the IR filter of IR MTF measuring system are described.

• ETRI Journal
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• v.34 no.1
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• pp.138-141
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• 2012

This letter proposes a real-time digital image stabilization system for cell phone cameras without the need for frame memory. The system post-processes an image captured with a safe shutter speed using an adaptive denoising filter and a global color correction algorithm. This system can transfer the normal brightness of an image previewed under long exposure to the captured image making it bright and crisp with low noise. It is even possible to take photos in low-light conditions. By not needing frame memory, the approach is feasible for integration into the size-constrained image sensors of cell phone cameras.

• Journal of IKEEE
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• v.23 no.4
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• pp.1465-1468
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• 2019

The image noise improvement algorithm proposed in this paper extracts the boundary line by using the window of the binarized image to detect the gesture motion. Boundary line blurring is prevented by improving Gaussian noise generated during video output. To improve gesture recognition in low-light environments, an image noise enhancement algorithm has been designed to provide an output image close to the base image. Analyzing the experimental results, we found almost 10% improvement in the results compared to the results of the existing Median filter.

• BMB Reports
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• v.35 no.4
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• pp.384-388
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• 2002

A method for the ratiometric pH sensing using LysoSensor DND-192 is presented in this paper. It works in the physiological pH range. It is based on the use of two fluorophores which differ significantly in their lifetimes. As the discrimination of their emissions is performed through two different frequencies, this method can allow significant overlap of the emission spectra. A simple long-pass filter, or a combination of long-and short-pass filters, was used instead of narrow-bandpass devices. Importantly, the measurements were carried out under strong ambient light. The method could be used in a wide variety of applications, such as intracellular measurements, microscopy, bioprocess monitoring, etc.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.513-516
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• 2002

The flow structure and heat transfer characteristics of a turbulent buoyant jet were investigated experimentally. The instantaneous temperature and velocity fields in the near field were measured using a two-frame PIV and PLIF techniques. A thin light sheet illuminated a two-dimensional cross section of the buoyant jet in which Rhodamine B was added as a fluorescent dye. The intensity variations of LIF signal from Rhodamine B molecules scattered by the laser light were captured by a CCD camera after passing an optical filter. By ensemble averaging the instantaneous temperature and velocity fields, the mean temperature and velocity fields as well as the spatial distributions of turbulent statistics were obtained. The results show the flow structure and convective heat transfer of the developing shear layer in the near field.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.2
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• pp.133-139
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• 2007

An unmanned ground vehicle can perform its mission automatically without human control in unknown environment. To move up to a destination in various surrounding situation, navigational information is indispensible. In order to be adopted for an unmanned vehicle, the navigation box is small, light weight and low power consumption. This paper suggests navigation system using a low grade MEMS IMU for supplying position, velocity, and attitude of an unmanned ground vehicle. This system consists of low cost and light weight MEMS sensors and a GPS receiver to meet unmanned vehicle requirements. The sensors are basically integrated by loosely coupled method using Kalman filter and internal algorithms are divided into initial alignment, sensor error compensation, and complex navigation algorithm. The performance of the designed navigation system has been analyzed by real time field test and compared to commercial tactical grade GPS/INS system.

• Proceedings of the IEEK Conference
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• 2000.06e
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• pp.117-120
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• 2000

Pulse oximetry is a well established non-invasive optical technique for monitoring the SpO$_2$ during anaesthesia, recovery and intensive care. Pulse oximeters determine the oxygen saturation level of blood by measuring the light absorption of arterial blood. The sensors consists of red and infrared light sources and photodetectors. In the measurement of the hemoglobin oxygen saturation, conventional method has required the technique of filtering of remove the noise, and of complex signal processing algorithm. So much time have required to signal processing. In this research, we separate AC signal and DC signal in the stage of signal detection. We filter the noise from each signal and convert A/D. We obtain the SpO$_2$ using the DSP algorithm.